1. Field of the Invention
The invention is directed to the field of electrical switches and more particularly to an electrical switch whose contacts are located within an insulating environmental enclosure operated by a mechanical system outside of the enclosure connected by a shaft extending through an enclosure seal.
2. Description of the Prior Art
In existing systems, the use of a reciprocating or rotating shaft extending through a seal into an insulating environment such as oil, SF or vacuum, can, due to wear of the seal adjacent such a shaft, permit the insulating media to leak out of the enclosure or permit air to enter the enclosure and destroy the vacuum and thus destroy the switch insulation. So as not to interfere with the movement of the operating shaft the seals had to be relatively thin and flexible and could not be located where it was possible to have the entire system voltage applied to them. This made the overall switch and operating device complex and quite large. To prevent loss of the insulating environment through a faulty seal the entire switch, including contacts and operating mechanisms could be placed in a large sealed chamber. However, this severally limited the possible locations for such a switch and often resulted in a location far from the system to be protected.